The discovery of hematuria in a child should lead the pediatrician to a methodical evaluation of the patient based on an extensive history and comprehensive physical examination. The microscopic examination of the urine is the cornerstone in the evaluation process and may suggest the origin of the hematuria. For instance, red blood cell casts indicate glomerular lesions and rule out the need for further urological examinations. According to the type of hematuria and the associated symptoms, a complete and immediate evaluation is sometimes necessary. This article presents a decisional tree to help the pediatrician to investigate an hematuria and to refer the child to a specialist, when needed.